Low expression of NQO1 predicts pathological complete response to neoadjuvant chemotherapy in breast cancer patients...

The aim of this study was to evaluate preoperative tumour expression of NAD(P)H:quinone oxidoreductase 1 (NQO1) along with other biological markers as potential predictors of pathological complete response (pCR) to neoadjuvant docetaxel, doxorubicin, and cyclophosphamide-containing (TAC) chemotherapy in patients with primary breast cancer. Sixty-one patients who received neoadjuvant chemotherapy (NCT) with TAC regimen were enrolled in this prospective study. The pre- and post- NCT expression of oestrogen receptor (ER), progesterone receptor (PR), epidermal growth factor receptor 1 and 2 (EGFR and HER2), NQO1, Ki-67 proliferation index, multidrug resistance protein 1 (MDR1), p53 and BCL2 were evaluated by immunohistochemistry. The pCR was reached in 14 patients (23 % of the study group). Multivariate analysis demonstrated that patients with ER-, PR-, NQO1- negative, and Ki-67-positive tumours had a significantly higher chance to achieve pCR. Within the biological subtypes, the highest pCR rate (50 %) was seen in triple-negative (i.e. ER-, PR-, HER2-) tumours. Post-operative evaluation showed that in comparison to pre-operative tissue samples, NQO1 expression was significantly increased, while Ki-67 and HER2 decreased, in the residual tissue after NCT. In conclusion, the present data suggests that NQO1 expression may be a novel diagnostic biomarker for the prediction of positive response to NCT in patients with breast cancer.